Our present invention relates to an apparatus for removing binder straps from articles which are provided with them, especially coils of metal strip. The coils of metal strip can be cold rolled strip as well as hot-rolled strip and the binding of the coil can be in the hot or cold state as well.
Coils can be bound with two or more binder straps each encircling the coil and spaced apart from one another over a region of the width of the coil. There are devices for removing such binder or tie straps and in general an apparatus for this purpose can comprise a blade cage in which a blade carriage is integrated and the blade cage can be displaced between working positions. The indication of an end position is usually effected with an inductive proximity switch.
The blade carriage can be equipped with a lifting wedge and a separating tool which can cut through the strap when the latter is lifted away form the coil. The lifting wedge is thus displaced along the coil surface and lifts the binder strap therefrom. The tool travels along behind the lifting wedge and severs the strap.
To allow the device to detect the binder strap, the conventional binder strap remover is also equipped with a sensor or detector which, on travel of the blade carriage over the coil surface, can detect the binder strap.
This system has the drawback that the sensor or detector is expensive and frequently unreliable. Since each binder strap is detected individually, the operations of lifting the binder strap and severing it are also carried out individually for each binder strap. Where multiple binder straps are provided on one coil, the device usually comes to a standstill between the binder strap removal operations. The operations is thus time-consuming and labor intensive. It is also prone to failure.
It is the principal object of the present invention to provide an apparatus or device for the removal of binder straps from articles encircled thereby, especially coils, whereby drawbacks of earlier systems are avoided.
A more specific object of this invention is to provide an apparatus for removing such a binder strap, especially from coils having a plurality of such straps, which eliminates the need for a binder strap sensor and hence the added cost of maintenance concerns for such a sensor and the element of unreliability which may be introduced thereby.
Still another object of the invention is to provide an apparatus for the purposes described which can eliminate the stepwise mode of operation hitherto required and provide a fully automatic removal of a plurality of binder straps, especially for articles like coils of metal strip.
These objects are attained, in accordance with the invention with a blade cage which can be brought into contact with an article provided with a plurality of binder straps, especially a coil of metal strip, having a blade cage with a drive for displacing the blade cage across the width of the coil and transversely to the binder strap thereon. This movement of the blade carriage is referred to as a stroke of the blade carriage. According to the invention, the blade carriage is formed with a lifting wedge for lifting the binder strap away from the periphery of the coil and a separating tool which operates in the region of the lifting wedge for cutting through the lifted binder strap.
The blade carriage is displaceable with a continuous stroke at least over a region of the coil width which is provided with the binder straps so that the binder straps are successively severed upon lifting by the wedge in a single continuous process, without stopping and without requiring a sensor for detecting those straps. More particularly, the apparatus according to the invention can comprise:
a blade cage engageable with each article;
a blade carriage displaceable on the cage along the width of each article and over the region from which binder straps are to be removed;
a lifting wedge on the blade carriage engageable beneath each binder strap in succession as the blade carriage is displaced along the width of the respective article;
a separating tool on the carriage cooperating with the lifting wedge for severing each binder strap lifted by the wedge; and
means on the cage connected with the blade carriage for continuously advancing the blade carriage across the region to automatically lift and sever all of the binder straps on a respective article in succession.
Where one or more binder straps are provided over a region of the width of the coil, the blade carriage is displaced in an uninterrupted stroke from one side of the region to the other, engaging each binder strap in turn and without interruption of its movement, lifting the binder straps successively and as each one is lifted, cutting them through with the aforementioned tool. The continuous and automatic operation is carried out without a sensor for the binder straps fully automatically.
The cutting tool is automatically moved against the lifted binder strap and can be a continuously driven blade or a blade which is entrained in rotation by its engagement with the binder strap.
Preferably, the cutting tool is a roller blade and this roller blade can define with the lifting wedge a predetermined cutting angle and can be entrained as the binder strap enters into the convergence between the blade and the lifting wedge in the course of the continuous displacement of the blade carriage across the region of the coil provided with the binder straps.
While the roller blade can be a continuously driven blade, preference is given to a blade free from a drive which is set into rotation as it engages a respective strap. The system of the invention has the advantage that it is relatively simple and does not require a sensor for the binder strap or a control of the cutting tool as has been conventionally required. The device is thus largely maintenance free and the operation of the device can be effected at minimum cost.
According to a feature of the invention, the lifting wedge is a stepped wedge having a pair of inclined ramp surfaces lying on opposite sides of a lifting tongue which projects forwardly of the inclined ramp surfaces in the direction of movement of the blade carriage across the region of the coil provided with the binder straps. In the center of the wedge a slit can be provided and the roller blade which forms the cutting tool can extend into this slit.
The wedge tongue can be especially flat and thus reliably can be forced beneath the strap simply by being guided along the surface of the coil to lift the strap. The lifting operation is facilitated by providing the lifting wedge with a relatively flat leading portion which initially engages beneath the strap and is followed by a steeper portion which displaces the strap away form the periphery of the coil.
The roller blade can be journaled about an axis which is disposed above the lifting wedge and extend orthogonally to the direction of displacement of the lifting wedge. The roller blade can thus be automatically set into rotation by engagement with the strap.
The blade carriage and the lifting wedge in the blade carriage can advantageously be provided with a spring suspension and can be resiliently biased against the coil surface so that the lifting wedge rests resiliently thereagainst. This elastic suspension can enable compensation for surface irregularities in the region of the coil surface.
At its side opposite that from which the tongue extends, the wedge can have a glide riding on the coil surface and preferably which is rounded and which serves to press the tongue portion of the wedge against the surface of the coil so that it reliably passes beneath the tensioned binder strap.
To facilitate the movement of the binder carriage along the coil, the latter can have wheels or rollers which ride along the coil surface. In addition, the blade carriage can have a hydraulic, pneumatic or electromagnetic drive which imparts the stroke to the blade carriage. The drive can have a lifting and lowering component as well as a traversing component. The drive thus serves to press the wedge against the coil surface in the starting position, to traverse the wedge over the aforementioned region of the coil in the working position and to lift the wedge away from the coil surface upon its return to the starting position in an end position of the carriage following the traverse. The limiting positions of the carriage can be defined by an inductive proximity switch, which, however, does not serve to detect the binder straps themselves and hence is not prone to the drawbacks of sensors of the type previously described.
According to a feature of the invention, the lifting wedge is formed with a lower clamping beam against which the separate ends of the strap may be clamped by an upper clamping beam. The upper clamping beam can thus be swung downwardly toward the lower clamping beam to engage the strap ends thereagainst. The clamping action can be effected also hydraulically, pneumatically or electromechanically and the clamping action and its release can be controlled by or engaged by an inductive proximity switch. The blade cage with the severed but clamped straps can be displaced into a disposal position at which the straps are released.
The binder straps which are cut free from the coil and can be wound or rolled up and after windup into a spiral can be discharged into a scrap bin.
The lower clamping beam can preferably have a wedge-shaped support surface for the strap ends and the upper clamping beam can have a pair of rounded portions straddling the support surface and clamping the strap ends against the support surface on opposite sides thereof.
According to a further feature of the invention the blade cage is provided with support wheels or rollers along opposite longitudinal sides of the cage and preferably swingably mounted on the cage. These rollers allow the blade cage to be urged against the outer surface of the coil and allow the blade cage to hold the binder straps against the coil until the upper and lower clamping beams engage the respective strap ends. The binder straps are thus also held in position during the engagement of the binder straps by the wedge and the severing tool.
The support rollers or wheels can be journaled in pairs on cheek plates which are pivotally connected to the cage.
To prevent the blade cage from shifting on the coil during the lifting and severing of the binder straps, the blade cage can have a retaining device which is effective in the direction opposite that for effecting the stroke of the blade carriage and which can engage behind the end face of the coil. This retaining device can also be hydraulically, pneumatically or electromechanically actuated. Following the severing process for the particular coil, the cage is lifted away from the coil and shifted to deposit the removed straps in the scrap bin. The retaining device is released at that point.
According to still another feature of the invention the cage has a bridged length over the coil and defining the stroke of the wedge and severing tool which is greater than the maximum distance between the two outermost binder straps which may be used in binding the coils which are to be operated upon by the apparatus of the invention. This ensures that a single stroke of the blade carriage will remove and retain all of the straps which can possibly be used for the coils employed.